Submission #670456

#	Time	Username	Problem	Language	Result	Execution time	Memory
670456		Sohsoh84	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	2749 ms	144468 KiB

joioi

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pll;

#define all(x)			(x).begin(),(x).end()
#define X			first
#define Y			second
#define sep			' '
#define endl			'\n'
#define debug(x)		cerr << #x << ": " <<  x << endl;

const ll MAXN = 2e3 + 10;

int G[MAXN][MAXN], n, m, ans, vis[MAXN][MAXN], mx, mn;

void add_cell(int x, int y, int dx, int dy) {
	if (x <= 0 || y <= 0 || x > n || y > m) return;
	if (vis[x][y]) return;

	vis[x][y] = true;	
	if (!mn) mn = mx = G[x][y];
	mn = min(mn, G[x][y]);
	mx = max(mx, G[x][y]);

	add_cell(x + dx, y, dx, dy);
	add_cell(x, y + dy, dx, dy);
}

inline void solve(int dx, int dy) {
	mx = mn = 0;
	vector<pair<int, pll>> vec;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			vec.push_back({G[i][j], {i, j}});
			vis[i][j] = false;
		}
	}

	sort(all(vec));
	ans = min(ans, vec.back().X - vec.front().X);
	int l = 0, r = int(vec.size()) - 1;

	while (l < r) {
		auto [xl, yl] = vec[l].Y;
		auto [xr, yr] = vec[r].Y;	
		if (vis[xl][yl]) {
			l++;
			continue;
		}

		if (vis[xr][yr]) {
			r--;
			continue;
		}

		add_cell(xl, yl, dx, dy);
		while (l <= r) {
			auto [xl, yl] = vec[l].Y;
			auto [xr, yr] = vec[r].Y;

			if (vis[xl][yl]) {
				l++;
				continue;
			}

			if (vis[xr][yr]) {
				r--;
				continue;
			}
			
			break;
		}

		if (l <= r)
			ans = min(ans, max(mx - mn, vec[r].X - vec[l].X));
	}
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			cin >> G[i][j];
		}
	}

	ans = numeric_limits<int>::max();
	solve(1, 1);
	solve(1, -1);
	solve(-1, 1);
	solve(-1, -1);
	
	cout << ans << endl;
	return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40